Life Strength
Men and women reach peak strength around 20 to 25 years of
age. After age 25, strength generally decreases an average of
1% per year. Therefore, a 65 year old would only have about 60%
of the strength they had at age 25. Individuals who are more
active, or those who continue to strength train, can considerably
decrease this tendency for declining muscular strength.
Strength training for older adults can reverse the loss of
muscle mass and enhance their ability to perform activities of
daily living.
Welle S. Resistance training in older persons. Clinical
Geriatrics 1998;6 (1):48-59.
Radakovich J. Prescribing resistance training for elderly
patients. Your Patient and Fitness 1997;11(2):27-30.
Strength Correlates to Muscle
Size
A muscle's strength has a strong relationship to its cross
sectional area in both men and women. Muscle enlargement with
a corresponding increase in strength was first shown scientifically
as early as 1897.
Ikai M, Fukunaga T, Calculation of muscle strength per
unit cross-sectional area of human muscle by means of ultrasonic
measurements. Int Z Angew Phsiol, 26:26-32, 1968.
Hetting T: Physiology of Strength. Springfield. Ill, C.
C Thomas, 1961.
Morpurgo B: U:ber Aktivita:ts-Hypertrophie der willkurlichen
Muskeln. Virchows Arch. Pathol Anat Physiol, 150:522-544, 1897.
Strength Recovery
Strength recovery was noted in an early exercise physiology
textbook. Elbow flexors were tested for strength and were worked
to exhaustion.
- 69% of strength was regained after 30 seconds of recovery
- 82% of strength was regained after 2.5 minutes
- 87% of strength was regained after 7.5 minutes
- 95% of strength was regained after 42.5 minutes
- only 26% more than what had been regained after a 30 second
rest
Morehouse LE, Augustus TM (1971), Physiology of exercise,
The C.V. Mosby Company, Saint Lois, 6th Ed, pg 60.
Fiber Types
Heavy resistance training can stimulate hypertrophy of both
Type I and II fibers, with Type II fiber experiencing the greatest
rate of hypertrophy. Also see Fiber
Type Comparison.
Gonyea & Sale 1882; Hakkinen & Komi 1985; Hakkinen,
et al 1989; MacDougall et al. 1980; Thorstensson 1976.
Combined Muscular Strength
It is estimated that if all the muscles of the human body
work together, that it could lift 11 tons, the equivalent of
4 SUVs.
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Neuromuscular Efficiency
Strength Training increases neuromuscular efficiency
- Increased number of motor units recruited
- Increased firing rate of each motor unit
- Increased synchronization of motor unit firing
Also see Motor Development.
Muscular Endurance
Resistance training incorporating high-volume, moderate-intensity,
and short rest periods, may increase capillarization in the muscles
(Schantz 1982; Tesch, et al. 1984). Bodybuilders who typically
perform this sort of training were able to exercise at a higher
percentage of their 1 rep max for 3 sets of 10 repetitions, compared
to powerlifters when plasma lactate concentrations were equally
elevated in both groups (Kreamer et al 1987).
Osteoporisis
Approximately 20 million women in the United States are affected
by osteoporosis, leading to multiple fractures and increased
hospitilizations.
Boning up on osteoporosis: a guide to prevention and treatment.
Washington, D.C.: National Osteoporosis Foundation, 1991.
Resistance training has been shown repeatedly to increase
bone marrow density, which can decrease the morbidity and mortality
resulting from osteoporosis.
Hamdy R., Anderson J, Whalen K, Harvill L. Regional differences
in bone density of young men involved in different exercises.
Medicine and Science in Sports and Exercise 1994; 26: 884-888.
Heinonen A, Oja P, Kannus P, Sievanen H, Manttari A, Vuori
I. Bone mineral density of female athletes in different sports.
Bone and Mineral 1993;23:1-14.
Karlson M., Johnell O. Obrant K. Bone mineral density in
weightlifters. Calcified Tissue International. 1993;52:212-215.
Nelson ME, Fiatarone MA, Morganti CM, Trice I, Greenberg
RA, Evans WJ. Effects of high intensity strength training on
multiple risk factors for osteoporotic fractures. A randomized
controlled trial. JAMA 1994;272(24):1909-1914.
Pocock NA, Eisman J, Gwinn T, Sambrook P, Kelly P, Freund
J, et al. Muscle strength, physical fitness, and weight but not
age to predict femoral neck bone mass. Journal of Bone and Mineral
Research 1989;4(3):441-448.
Menkes A, Mazel S, Redmond RA, Koffler K, Libanati CR,
Gundberg CM, et al. Strength training increases regional bone
mineral density and bone remodeling in middle-aged and older
men. Journal of Applied Physiology 1993; 74(5):2478-2484.
Early Kinesiology Study
FE Nipher, Assistant Professor of Physics in Washington University
(1875). On the Mechanical work done by a muscle before exhaustion.
American Journal of Science and Arts. 9(100), 130-137.
From America's first scientific journal: mentions strength
adaptation, daily work volume (kgr.-meters), dynamometer; differentiates
'static work' versus 'dynamic work'.
Dumbbell Origin
"The original dumbbell was an apparatus contrived like
that for ringing church-bells; that is, a heavy fly-wheel with
a weight attached, which was set in motion like a church-bell,
until it acquired sufficient impetus to carry the gymnast up
and down, and so bring the muscles into active play. There is
one at New College, Oxford, to the present day. The modern weights,
so called, produce similar results, in a less cumbrous and more
agreeable manner." - Edwards's Words, Facts, and Phrases.
Phyfe WHP (1901) Five Thousand Facts and Fancies, GP Putnam's
Sons, pg 250.
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